WO2013120032A1

WO2013120032A1 - System and methods for improved satellite communications

Info

Publication number: WO2013120032A1
Application number: PCT/US2013/025453
Authority: WO
Inventors: Michael A. Leabman
Original assignee: Truepath Holdings Llc
Priority date: 2012-02-09
Filing date: 2013-02-08
Publication date: 2013-08-15

Abstract

The present invention relates to systems and methods for an advanced satellite communication antenna for use on a mobile platform. The antenna would include an array of element that is flat and have a diameter of above 24 inches. At least 256 elements are required, and typically 1000 elements may exist on the array. Close to the elements is a plurality of analog RF circuits. These circuits control the gain and phase of the elements in order to form a beam and steer nulls. One or more digital controllers attach to the analog circuits to control the beam direction. These may be more than one layer of digital or analog RF circuits between the first layer of circuits and the final digital circuit. The array may be on an incline of 5-30 degrees and mounted on a rotating base.

Description

SYSTEM AND METHODS FOR IMPROVED SATELLITE COMMUNICATIONS

BACKGROUND

[0001] The present invention relates to improved antenna arrays and methods of operation in order to increase satellite communications from a mobile receiver. More particularly, the present invention relates to an antenna array that enables fewer moving parts, has a more flat profile than existing parabolic satellite dishes, and can nearly instantaneously track a target.

[0002] Satellite communications have become increasingly important for military and commercial applications. Satellite communications enable large bandwidth, and rapid data transmission. Traditionally, satellite communication employs parabolic dish devices. These parabolic antennas are capable of focusing transmissions collect radio frequency (RF) signals from the satellite. However, in order to have proper signal, the parabolic dish needs to be oriented toward the satellite.

[0003] For stationary receivers in communication with geosynchronous satellites, this is a relatively mundane task. The parabolic dish merely needs to be affixed to the static location in the proper orientation. However, for mobile receivers, such as boats, tanks, missiles, aircraft, or other vehicles, the proper orientation of the parabolic dish is more complicated. For these mobile devices, the parabolic antenna needs to be movable, both in altitude and azimuth. This requires a number of moving parts, which adds to expense and reliability concerns. Further, mechanically orienting a beam is much slower than desired for fast moving mobile objects (such as a missile for example).

[0004] Additionally, these parabolic dishes with their complicated movable bases are rather obtrusive. This makes these devices more susceptible to damage by enemy fire, weather, or other natural hazards. Additionally for fast moving objects, such as missiles, high profile parabolic dishes may generate unwanted drag.

[0005] In an attempt to address the issue of size, companies such as EMS have developed antenna patches which are flat in design. These antenna patches include an array of transmitting elements. The current EMS antenna patch is available in a 35 inch by 6 inch geometry. These flat antenna patches utilize known means of signal reinforcement and interference to focus the RF signal in a particular direction. This technique is known as "beamforming", and can be used to reduce the reliance upon physical movement of the array, or parabolic surfaces, in order to properly target an object (such as a satellite) from a moving receiver.

[0006] While such systems are dramatic improvements over parabolic dishes in terms of profile, the antenna arrays offered by current suppliers is sorely lacking in off-axis limits for large skew due to their narrowness in one direction. That is, at large skew the equivalent isotropically radiated power (EIRP) spectral density exceeds limits imposed by the Federal Communications Commission (FCC) for off-axis. Even for no skew, the EIRP profile for such systems is dangerously close to FCC limits. As such, current flat panel parabolic substitutes are still greatly lacking because they require substantial moving bases (including both azimuth and altitude movement) in order to operate effectively.

[0007] It is therefore apparent that an urgent need exists for an improved satellite antenna that has a low profile and reduced reliance upon a moving base, as well as methods for its use. Such a system will reduce costs for antennas, increase reliability, and reduce susceptibility to damage, all while complying with FCC regulations.

SUMMARY

[0008] To achieve the foregoing and in accordance with the present invention, systems and methods for an advanced satellite communication antenna for use on a mobile platform, such as a boat, land vehicle or airplane for example. The antenna would include an array of element. The array would be flat and have a diameter of above 24 inches. At least 256 elements are required, and typically 1000 elements may exist on the array. The elements are vertical pole, horizontal pole, circularly polarized, left hand polarized, right hand polarized, or a combination of polarizations.

[0009] Close to the elements is a plurality of analog RF circuits. These circuits control the gain and phase of the elements in order to form a beam and steer nulls. One or more digital controllers attach to the analog circuits to control the beam direction. These may be more than one layer of digital or analog RF circuits between the first layer of circuits and the final digital circuit. In some embodiments, each element is coupled to a corresponding RF circuit. In other cases, a group of elements couple to a single controlling circuit. [0010] In some cases, the elements are located on more than one surface.

Sometimes the array may be on an incline of 5-30 degrees and mounted on a rotating base. This allows the base to rotate around an azimuth and the panel can beam form in the elevation in order to target the satellite. Nulls can be steered around the beam enabling larger power to be used in the array and still stay below the FCC limits for side lobe energy density. This is known as "beamshaping".

[0011] Note that the various features of the present invention described above may be practiced alone or in combination. These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order that the present invention may be more clearly ascertained, some embodiments will now be described, by way of example, with reference to the

accompanying drawings, in which:

[0013] Figures 1A to 1C are example schematics illustrating mobile receivers communicating with a satellite, in accordance with some embodiment;

[0014] Figure 2 A is an example schematic illustrating a known parabolic antenna design, in accordance with some embodiment;

[0015] Figure 2B is an example schematic illustrating a known flat panel antenna array design, in accordance with some embodiment;

[0016] Figure 3 is a schematic illustrating a novel flat panel antenna array design, in accordance with some embodiment;

[0017] Figures 4A to 4C are example logical schematics for implementations of the novel flat panel antenna array, in accordance with some embodiment;

[0018] Figure 5 is an example graph of equivalent isotropically radiated power versus off axis angle with no skew for known antenna and the novel flat panel antenna array, in accordance with some embodiment; [0019] Figure 6 is an example graph of equivalent isotropically radiated power versus off axis angle with 90° skew for known antenna and a first novel flat panel antenna array, in accordance with some embodiment;

[0020] Figure 7 is an example graph of equivalent isotropically radiated power versus off axis angle with varying levels of skew for known antenna and the novel flat panel antenna array, in accordance with some embodiment;

[0021] Figure 8 is an example graph of equivalent isotropically radiated power versus off axis angle with varying levels of skew for known antenna and the novel flat panel antenna array with null steering, in accordance with some embodiment;

[0022] Figure 9 is an example schematic illustrating of a possible mounting geometry for the novel flat panel antenna array design, in accordance with some

embodiment; and

[0023] Figure 10 is an example flowchart for the process of satellite communication with the novel flat panel antenna array design, in accordance with some embodiment.

DETAILED DESCRIPTION

[0024] The present invention will now be described in detail with reference to several embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, to one skilled in the art, that embodiments may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. The features and advantages of embodiments may be better understood with reference to the drawings and discussions that follow.

[0025] The present invention relates to systems and methods for improved satellite communication. In particular, a novel flat panel array is proposed which enables a thinner profile and reduction of moving parts as compared to known parabolic antenna and known flat panel arrays. These novel panels have particular use in association with mobile receivers such as boats, aircraft, tanks, armored personnel carriers, missiles, and other vehicles in communication with a satellite. [0026] While much of this application will center on transmission between a mobile receiver and a satellite, it should be understood that the present disclosure applies equally well to other communication between any mobile receiver and either a stationary or moving target. Thus, these novel antenna designs may be used, for example, for communications between commercial aircraft and base stations, between boat and aircraft, between land vehicle and radio tower, or any other viable combination.

I. OVERVIEW

[0027] To facilitate the discussion, Figure 1 A is provided as showing an example schematic illustrating a mobile receiver 102 communicating with a satellite 108, shown generally at 100. Here the mobile receiver 108 is illustrated as a naval cargo ship; however, as previously discussed, any mobile platform may be utilized, including land vehicles, aircraft, missiles, drones, submersibles, or the like. Further, while the mobile receiver 102 is illustrated as communicating with a satellite 108, it should be notes that communications with any viable target is equally possible. This includes base stations or other mobile platforms.

[0028] The mobile receiver 102 includes an antenna 104 to communicate with the satellite 108 (seen at 106). The antenna, as will be discussed, may include a parabolic dish, or flat paneled system. In some particular embodiments, novel flat panel systems are usable, as will be discussed in greater detail below.

[0029] Regardless of antenna 104 type, a directional beam 106 is directed from the antenna 104 to the satellite 108. Directionality may be accomplished through physical geometry (i.e., parabolic dish) or through signal reinforcement/interference (i.e., beamforming).

[0030] Figure IB similarly illustrates the antenna mounted on two land vehicles, a news van 110 and a search and rescue vehicle 112, respectively. Each land vehicle includes an antenna 104 communicating with the satellite 108. Lastly, Figure 1C illustrates a flying mobile receiver, here a police airplane 114, including an antenna 104 communicating with the satellite 108. The purpose of these illustrations is to better illustrate the wide range of applications that satellite communications including moving platforms that exist.

[0031] Figure 2 A is an example schematic illustrating a known parabolic antenna design 104a, in accordance with some embodiment. Currently, most military, commercial and personal satellite communication antennas are parabolic. These systems include a parabolic dish 202 and header 204. The parabolic dish focuses incoming RF signals onto the header 204, and likewise, omnidirectional transmissions from the header 204 are linearized by the parabolic dish 202 for directional transmission.

[0032] The dish 202 is held by a base 206 capable of azimuth and altitude movements. This allows the parabolic antenna to be directed towards any object above the horizon. Consequently, the cost of a parabolic antenna in dramatically increased, and with so many moving parts, reliability of the unit is of concern.

[0033] Also noteworthy, the parabolic dish 202 and base 206 has a prominent profile that extends well above the surface of the mobile platform 102. This makes it more susceptible to the elements and damage.

[0034] Conversely, Figure 2B is an example schematic illustrating a flat panel antenna array design 104b similar to known array patches, in accordance with some embodiment. This example array design is similar to that manufactured by EMS for satellite communication. In this array, a series of 455 elements are laid out in a 6 inch by 34 inch geometry. The EMS system has different patch geometry; however, overall size and layout are similar to the illustrated array. The EMS panel has fixed wiring, thus there are no analog RF adjustments. Individual, or subset control, over the array elements enable beamforming of the resulting output for at least some degree of transmission directionality. This eliminates the need for a parabolic surface, and therefore allows the EMS array a much smaller profile. However, due to intrinsic limitations in the geometry, and fixed wiring control, of the EMS array, off-axis angle limits (set by the FCC) are exceeded when any significant skew is present. As such, such an array still requires substantial mechanical systems to minimize array skew (including azimuth and altitude movement).

II. BEAMFORMING

[0035] The term beamforming derives from the fact that early spatial filters were designed to form pencil beams in order to receive a signal radiating from a specific location and attenuate signals from other locations. "Forming beams" seems to indicate radiation of energy; however, beamforming is applicable to either radiation or reception of energy.

[0036] Systems designed to receive spatially propagating signals often encounter the presence of interference signals. If the desired signal and interferers occupy the same temporal frequency band, then temporal filtering cannot be used to separate signal from interference. However, the desired and interfering signals usually originate from different spatial locations. This spatial separation can be exploited to separate signal from

interference using a spatial filter at the receiver. Implementing a temporal filter requires processing of data collected over a temporal aperture. Similarly, implementing a spatial filter requires processing of data collected over a spatial aperture.

[0037] In some embodiments, a beamformer linearly combines the spatially sampled time series from each sensor to obtain a scalar output time series in the same manner that an FIR (finite impulse response) filter linearly combines temporally sampled data. Spatial discrimination capability depends on the size of the spatial aperture; as the aperture increases, discrimination improves. The absolute aperture size is not important, rather its size in wavelengths is the critical parameter. A single physical antenna

(continuous spatial aperture) capable of providing the requisite discrimination is often practical for high frequency signals since the wavelength is short. However, when low frequency signals are of interest, an array of sensors can often synthesize a much larger spatial aperture than that practical with a single physical antenna. Note, each composite antenna represents a sensor in some embodiments.

[0038] A second very significant advantage of using an array of sensors, relevant at any wavelength, is the spatial filtering versatility offered by discrete sampling. In many application areas it is necessary to change the spatial filtering function in real time to maintain effective suppression of interfering signals. This change is easily implemented in a discretely sampled system by changing the way in which the beamformer linearly combines the sensor data. Changing the spatial filtering function of a continuous aperture antenna is impractical.

[0039] Beamforming takes advantage of interference to change the directionality of the array whereby constructive interference generates a beam and destructive interference generates the null space.

[0040] If one issue of current satellite communication antennas on mobile platforms

102 is the inherent cost, bulk and unreliability of moving mechanical bases, it is desirable to use and be able to change the direction in which RF emissions radiate using non-mechanical means. Beamforming using a smart antenna array, during transmission, is accomplished by controlling the phase and/or relative amplitude of the signal at each transmitter, in order to create a pattern of constructive and destructive interference in the wave front. Similarly, when receiving, information from different sensors is combined in such a way that the expected pattern of radiation is preferentially observed (null steering). The antenna array built by EMS performs some degree of beamforming; however, due to geometric limitations, these antenna's are incapable of achieving in-limit equivalent isotropically radiated power (EIRP) in off-axis angles when skew is present.

[0041] The ability to beamform in this manner requires a minimum of two antennas in the antenna array. This directionality benefit of beamforming has been known generally by those skilled in the art for some time. In general, beamforming may be accomplished in a number of known ways, as is known by those skilled in the art. For an example of a particular method of implementing directional beamforming, see: B. D. V. Veen and K. M. Buckley. Beamforming: A versatile approach to spatial filtering. IEEE ASSP Magazine, pages 4-24, Apr. 1988.

[0042] An additional example of the mathematics behind beamforming may be found in the article by Michael Leabman entitled Adaptive Band-Partitioning for

Interference Cancellation in Communication Systems. Massachusetts Institute of

Technology Press, February 1997.

[0043] Most array literature specifies spatial dependence in terms "angles" which is intuitive. It is also possible to define the wavenumber variable k which is a spatial vector in terms of Euclidean space, where, \ k \= colc , (o being the radian frequency (2πί), and c being the propagation speed in free space. Thus | k |= ωΙ c = 2 I c = 2πΙ λ has dimensions of 1/length, where the wavelength λ = f I c , and c = 3* 10⁸ m/s for radio waves. While the standard angular representation does describe the response over the region for all real signals, the full wavenumber space, or 'virtual' space, is more useful in analyzing the consequences of spatial aliasing.

[0044] Now consider an array of N elements sampling an area of space where the element locations are governed by [z . , i = 1 , ... , N] . The output from each sensor is input to a linear, time invariant filter having the impulse response Wi (τ). The outputs of the filter are summed to produce the output of the array y(t),

[0045] y(t)

_∞ w_t {t - τ) X{T, z_t )dT

i=l [0046] Using the Fourier representation for a space-time signal, a plane wave x(t, z_i ) of a single frequency may be represented by a complex exponential in terms of a radian frequency ω, and vector wavenumber k :

[0047] x(t, . ) = e^²'-) [0048] The array response to a plane wave is as follows:

[0049]

i=l

N , >

[0050]

i=\

[0051] ' ^where = t - 1'

N

^'[ait-k-z,

[0052]

i=l [0053] letting,

[0055] becomes j(t) = W ⁺ {(o)E{k)e^iax

[0056] where w[ o, k ) = W⁺ (co)E(k) is the frequency wavenumber response. The frequency wavenumber response evaluated versus direction k , is known as the

beampattern,

[0057] Β{α(θ, φ)) = ψ[ω,ί) ΐ _{2π t}

[0058] where a(6, ) is the unit vector in spherical coordinates.

[0059] The most widely used array, suitable for some embodiments, is a linear uniformly weighted array with N elements and an inter-element spacing of Δζ. Note, such an array is used by way of example, and other array designs are considered within the scope of this invention. [0060] If a frequency independent uniform weighting of 1/N is used, a frequency wavenumber response is arrived at:

N-l

2

[0061] W(co,k) =— j ^^{B Az} , where k^■

N N-l

7.71

[0063] Evaluating for k_z =| k | sin(/9) =— sin(/9), where Θ is defined with respect to λ

the angle to the z axis, a beampattern is calculated as:

[0064] Β(ω, θ) = where L= NAz.

[0065] In some embodiments, combinations of beams and nulls may be utilized in order to increase gain in the target axis, while reducing the EIRP in off axis angles. With more antennas on the array the number of beams/nulls is extendable to meet any specialized requirements.

III. NOVEL ANTENNA ARRAY DESIGN

[0066] By leveraging advanced beamforming techniques, two means for improved systems design are provided: one is a novel combination of known antenna arrays with unique control mechanisms and the other includes the utilization of a novel antenna array.

[0067] In the first means for an improved satellite communication system, two of the antenna patches illustrated in Figure 2B may be utilized together in order to implement beam-nulling around mechanically point angle. This enables a suppression of off-axis sidelobes, and thus a greater degree of compliance with FCC regulations.

[0068] Figure 5 illustrates a graph 500 of the equivalent isotropically radiated power

(EIRP) spectral density versus the off-axis angle for a EMS known flat panel (similar to that seen in Figure 2B, shown at line 520) and the presently disclosed system of two similar panels with beam-nulling (shown at line 530). The limits imposed by the Federal

Communications Commission (FCC) are seen at the dotted line 510. The graph illustrates the panels at no skew. Even so, the known panel fails to comply with the FCC limits after 3-4 degrees. Conversely, the disclosed beam-nulling system suppresses the sidelobes up to 7 degrees. For larger off-axis angles, a deep null can be generated for close in satellites.

[0069] Moving to Figure 6, a graph 600 is illustrated that compares the known flat panel at a near 90 degree skew (shown at line 620) to the disclosed beam-nulling at a similar skew (at line 630). Again the FCC limits for off-axis EIRP is illustrated as a dotted line 610. Of note is that both the disclosed system and that of the known panel exceed the FCC limits at a 90 degree skew. However the newly disclosed system is capable of steering the deep null (seen at about -3 degrees off-axis). Thus, if one or two satellites are close, these nulls may be steered toward these satellites in order to remain in compliance. While this is an improvement over the known flat panel antennas, more than two satellites in range will render such a system out of FCC compliance. The purpose of the graphs of Figures 5 and 6 is to illustrate that the known flat panel antenna, and even the modified beam nulling setup disclosed herein, are incapable of compliant operation at a high degree of skew. Thus, these designs necessitate being mounted on a base that has both azimuth and altitude movement.

[0070] The second mechanism that enables a smaller antenna profile, and reduced need for a moving base, includes an improved antenna design that enables superior beamforming control. Such an antenna could conceivably be flush mounted to the mobile platform, and be able to target its beam from horizon to zenith in all directions. Figure 3 is a schematic illustrating of such a novel flat panel antenna array design 300. This antenna array is illustrated as including 1005 separate elements in a circular arrangement 34 inches in diameter. Alternate permutations are also possible including cut-off circular pattern, square, or other polygon. Additionally, this array may be broken into numerous pieces and distributed across multiple surfaces (multi-faceted). However, the larger size in both axes as compared to the other known 6x36 inch arrays is required. While other numbers of elements are possible, the gain requirements for satellite communications favor at least 1000 elements. In some embodiments where size is an issue, it is possible for the antenna to be as low as 24 inches in diameter, and include as few as possibly 256 elements.

[0071] Figures 4A to 4C illustrate detailed cross section illustration of the schematic components of the novel flat panel antenna array 300 for various embodiments. In Figure 4 A, the elements 402 are seen on a substrate layer 404. The elements 402 may be horizontal pole, vertical pole, circular polarized, left hand polarized, right hand polarized or some combination thereof. The substrate layer 404 provides mechanical stability and heat absorption properties, for example. Wires can be seen extending from each element 402 to a corresponding RF circuit 406. Due to the processing requirements of 1005 individual elements, a combination of analog RF circuits 406 and one or more digital circuit(s) may be utilized to reduce processing requirements. However, since these elements are putting out very small signals, it is desirous that the analog RF circuits 404 are physically closely aligned with the elements 402 in order to minimize loss. The phase and amplitude of each element 402 may be modulated by the respective RF circuit 404 in order to generate the desired beamform and null steering.

[0072] While Figure 4 A illustrates an array 300a that has each element 402 coupled to a single RF circuit 406, in Figure 4B an array 300b is illustrated where a subset of the elements 402 are coupled to a single RF circuit 406. In this example, the RF circuit 406 couples to four elements 402. More or fewer elements 402 may be controlled by each RF circuit 406, in some embodiments. The determination of the required number of elements to be coupled to a singe controller may be based entirely upon processing requirements, desired array cost, and the needs of the final application. In some applications, very high levels of control and granularity may be desired, resulting in a lower ratio of controllers to elements. In other applications, fewer controllers are needed because beams control can be less granular.

[0073] For example, in Figure 4C an array 300c is illustrated where a pair of elements 402 couple to a single RF circuit 406. This provides greater control over beamforming than the previous example which coupled one controller to four elements. Two of these RF circuits may then couple to a second layer analog RF circuit 408. In turn, two of the second layer RF circuits 408 may couple to a single final RF circuit 410. This RF circuit 410 may be an analog or digital circuit.

[0074] In many embodiments, this multilayered system of several-to-many controllers may be employed. For example, in some embodiment, an array of 1000 elements may include a first layer of RF circuits that service 10 elements apiece (100 RF circuits). Ten of these RF circuits may feed to a second layer RF circuit (10 second layer RF circuits). These 10 second layer RF circuits then feeds to a final RF circuit. Such a "nested" RF circuit design may be able to provide better control over beamforming than current systems.

[0075] In many embodiments, all the phasing is done in analog and groups of elements can be combined in analog before going to digital. In some embodiments, all the elements are combined with analog RF circuit and then one digital RF circuit. In other embodiments, a group of elements may be controlled using analog RF circuits, and then these groups may be combined using a smaller group of digital RF circuits. For example, every horizontal row of say 36 elements could be combined in analog, and then the output of these 35 rows combined in digital.

[0076] The array embodiments illustrated in relation to Figure 3 and 4A-4C enable greater beamforming control over the off-axis sidelobes, even at a significant skew. Figure 7 is an example graph 700 of equivalent isotropically radiated power versus off axis angle with varying levels of skew for known antenna and the novel flat panel antenna array 300. This graph illustrates the known flat panel array similar to Figure 2B at a 90 degree skew at line 720. Clearly, the energy profile for this array exceeds the FCC limits 710 for off-axis angles. However, the novel array at 45, 60 and even 90 degree skew (shown at lines 730, 740 and 750, respectively) has a spectral density well within the FCC limits. This means that the novel array may be fixed, and even though the array is static, it may be able to beamform in any direction above horizon. This has very substantial impact upon the utility of the array.

[0077] Beamforming is nearly instantaneous, whereas mechanical movement of a beam is comparatively very slow. Thus such an array may track a moving object (in relation to the mobile platform) much more tightly than mechanically dependent antennas. Further, the flat geometry of such an antenna, and the ability for the array to be static, enables a nearly flush profile. On very fast moving objects, or those prone to elemental or human damage, this profile may prevent significant drag or damage of the array. Moreover, the lack of complex moving parts reduces maintenance and possible mechanical failures of the antenna compared to traditional antennas. Finally, the cost of such an array is significantly lower than those which rely upon mechanical hardware.

[0078] In addition to all of the advantages enumerated above, it should also be noted that an array 300 of this sort has very close control of null spaces. This allows the array to "beamshape" by steering null spaces around the central beamform. This substantially suppresses sidelobes, as can be seen on Figure 8 which shows an example graph 800 of equivalent isotropically radiated power versus off axis angle with varying levels of skew for known antenna and the novel flat panel antenna array with null steering. The traditional flat panel at 90 degree skew is again seen at line 820, well outside of the FCC envelope 810. The novel antenna array at 45, 60 and 90 degree skew (seen at lines 830, 840 and 850, respectively) are all well within the FCC limits. In fact these sidelobes are roughly 10 dB below the FCC limits. This enables the output power to be increased significantly, thereby enabling greater amounts of data to be transmitted even compared to traditional parabolic antennas. In fact, through higher output power, 2-3 times the bandwidth can be realized, as compared to standard parabolic antennas.

[0079] While it is possible to design a system which utilizes beamforming for directionality entirely, and can therefore be fixed, beamforming near the horizon (at a 90° skew) can still often be difficult. Thus, an additional mounting system is proposed whereby the array 300 is placed on a minor incline (a 5-30° incline is sufficient), and the azimuth may be mechanically controlled by a turntable-like base. An example schematic illustrating of such a system is provided in Figure 9, shown generally at 900. Here the novel round array 300 may mounted on a base 902 capable of rotating around a vertical axis 904). The array may be configured to control altitude through beamforming entirely, and rely upon mechanical means for the azimuth orientation. In some embodiments, limited azimuth beamforming may also be employed to correct for sudden movements as these adjustments can occur much faster than mechanical adjustments.

[0080] Lastly, Figure 10 is an example flowchart for the process of satellite communication with the novel flat panel antenna array 300. In this example process, the array 300 is rotated across the azimuth by the base 902 (at 1002) such that the azimuth orientation is matching the target. The beam may then be calibrated such that it hits the target (at 1004). This calibration includes beamforming along the proper altitude, and optionally beamforming along the azimuth when required for rapid corrections due to sudden movements of the mobile platform or the satellite.

[0081] Then, optionally, the null space may be steered around the beam (at 1006) in order to suppress the sidelobes. This may be known as beamshaping, as discussed above. Lastly, data may be transmitted and received (at 1008) by the antenna array 300. The array may constantly adjust beam direction and base rotation in order to ensure connection fidelity. [0082] In sum, systems and methods for wireless broadband data communication between a moving receiver and a satellite are provided. While a number of specific examples have been provided to aid in the explanation of the present invention, it is intended that the given examples expand, rather than limit the scope of the invention. Although sub-section titles have been provided to aid in the description of the invention, these titles are merely illustrative and are not intended to limit the scope of the present invention.

[0083] While the system and methods has been described in functional terms, embodiments of the present invention may include entirely hardware, entirely software or some combination of the two. Additionally, manual performance of any of the methods disclosed is considered as disclosed by the present invention.

[0084] Additionally, while this invention has been described in terms of several preferred embodiments, there are alterations, permutations, modifications and various substitute equivalents, which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and systems of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, modifications, and various substitute equivalents as fall within the true spirit and scope of the present invention.

Claims

CLAIMS What is claimed is:

1. An advanced satellite communication antenna, useful in association with a mobile platform, the antenna comprising: an array of a plurality of elements arranged such that the array is substantially flat, and such that each of the array length and the array width is above 24 inches; a plurality of analog radio frequency circuits coupled to the plurality of elements, wherein the plurality of analog radio frequency circuits is oriented substantially adjacent to the plurality of elements, and wherein the plurality of analog radio frequency circuits modulates the gain and phase of the plurality of elements; and at least one digital controller coupled to the plurality of analog radio frequency circuits.

2. The antenna of claim 1, wherein each of the plurality of analog radio frequency circuits couples to a single corresponding element.

3. The antenna of claim 1, wherein each of the plurality of analog radio frequency circuits couples to a subset of elements of the plurality of elements.

4. The antenna of claim 1, wherein there are approximately 1000 elements.

5. The antenna of claim 1, wherein the plurality of elements are at least one of vertical pole, horizontal pole, circularly polarized, left hand polarized, right hand polarized, and a combination of polarizations.

6. The antenna of claim 1, wherein the plurality of elements are located on more than one surface.

7. The antenna of claim 1, wherein the array is at an incline.

8. The antenna of claim 7, wherein the incline is approximately between 5 and 20 degrees.

9. The antenna of claim 7, further comprising a base upon which the inclined array is mounted, wherein the base is capable of rotation about a vertical axis.

10. The antenna of claim 9, wherein a processor mechanically orients the array around an azimuth and beamforms along an altitude such that the beam substantially intersects a satellite.

11. The antenna of claim 10, wherein the processor steers at least one null substantially adjacent to the beamform in order to beamshape.

12. The antenna of claim 10, wherein the processor includes the at least one digital controller.

13. The antenna of claim 1, further comprising a second layer of radio frequency circuits, wherein each of the second layer radio frequency circuits couples to a subset of the plurality of analog radio frequency circuits.

14. The antenna of claim 13, further comprising a third layer of radio frequency circuits, wherein each of the third layer radio frequency circuits couples to a subset of the second layer of radio frequency circuits.

15. The antenna of claim 14, wherein the at least one digital controller couples to the third layer of radio frequency circuits.

16. A method for satellite communication comprising: mechanically orienting a flat array antenna including a plurality of elements around an azimuth using a rotating base; forming a beam in a specific altitude using the array, wherein the forming of the beam in the specific altitude and the mechanical orientation around the azimuth directs the beam to a satellite; steering at least one null substantially adjacent to the beam such that the beam sidelobes are depressed below the limits imposed by the Federal Communications Commission; and transmitting and receiving data over the beam using radio frequency radiation.